What are the phenomena of "running, emitting, dripping, and leaking" in the multi-stage pump valves of Dalian Chemical Pump?

In the petrochemical industry, multi-stage pumps are commonly used equipment, and the phenomenon of "running, emitting, dripping, and leaking" of pipeline valves is quite common. The best way to solve the problem of "running, emitting, dripping, and leaking" is to prevent it before it happens. How to detect problems before valve failure and avoid accidents? This article mainly summarizes the "eight leakage" control and prevention measures for oil leakage, water leakage, steam leakage, smoke leakage, ash leakage, coal leakage, powder leakage, and gas leakage for reference.

What we usually refer to as leakage and dripping mainly refers to the loss of liquid transported through pipelines that overflows the container at the source, process, and terminal of transportation, invisible leakage in hidden pipelines, dripping at interfaces and valves, and flow caused by liquid level control. An effective engineering system and management should have effective measures to eliminate the above-mentioned phenomena.

1、 Prevent valve leakage and steam leakage

1. All valves shall undergo different levels of hydrostatic testing after entering the factory.

Valves that require disassembly and maintenance must be ground.

3. During the maintenance process, carefully check for the addition of packing and whether the packing cover is tightened.

Before installation, check whether there are dust, sand particles, iron oxide and other impurities inside the valve. If there are any of the above-mentioned debris, they must be cleaned before installation.

5. All valves must be equipped with gaskets of the corresponding grade before installation.

6. When installing the flange door, tighten the fasteners and tighten the flange bolts in a symmetrical direction in sequence.

During the valve installation process, the valve must be installed correctly according to the system and pressure, and it is strictly prohibited to install it randomly, mix it up, or install it in reverse. All valves must be numbered according to the system and recorded before installation.

2、 Prevent the interface between equipment and fittings from running, emitting, dripping, or leaking

Flange gaskets above 1.2.5Mpa are all made of metal wrapped gaskets.

2.1.0Mpa to 2.5Mpa flange sealing gasket, using asbestos gasket and coated with black lead powder.

Rubber gaskets shall be used for flange sealing of water pipes below 3.1.0Mpa, and black lead powder shall be applied.

4. The packing of chemical pumps is made of PTFE fiber composite packing.

5. For the sealing parts of smoke, air and coal pipelines, the asbestos rope used should be twisted and smoothly added to the joint surface at once. It is strictly prohibited to add it forcefully after tightening the screws.

3、 Prevent valve leakage

1. During pipeline installation and construction, it is necessary to establish a good quality awareness, consciously clean the oxide scale and the inner wall of the pipeline, leave no debris, and ensure that the inner wall of the pipeline is clean.

3. Firstly, ensure that all valves entering the site undergo a 100% hydrostatic test.

3. Valve grinding should be carried out carefully, and all valves (except for inlet valves) are required to be sent to the grinding team for disassembly, inspection, grinding, and maintenance. Responsibilities should be implemented, and records and markings should be made consciously for traceability. Important valves should be listed in detail for secondary acceptance, meeting the requirements of "stamping, inspection, and recording".

4. When flushing the pipeline, it is necessary to turn it on and off lightly to prevent damage to the valve core.

4、 Correct operation of valves

1. Whether you understand the valve manual or not, you must operate according to the instructions.

2. When opening and closing the valve, do not apply too much force or force. Do not exceed the upper limit when opening the valve. After fully opening the valve, the handwheel should be turned back a little or 1 turn;

3. The connection between the handle or handwheel and the valve stem should be firm, and there should be a stopper at the threaded connection;

4. The fasteners used for connection should withstand the corrosion of the medium and have certain mechanical strength and wear resistance.

5. Do not easily use force rods for normally used valves.

6. Do not have two people working together to open or close the valve.

7. When closing the valve, do not use excessive force just because you are worried about not closing it tightly. The force of the tight hand is sufficient.

When the valve is stopped, lubricating oil and other necessary maintenance should be added.

5、 Preventive measures for coal powder leakage

1. All flanges must be installed with sealing materials.

The areas prone to powder leakage are the inlet and outlet coal valves of the coal mill, the coal feeder, the manufacturer's flange, and all parts connected by flanges. For this purpose, a comprehensive inspection should be conducted on all parts of the manufacturer's equipment that are likely to leak powder. If no sealing material is installed, a secondary installation should be carried out, and the fasteners should be tightened.

3. If there is a possibility of powder leakage at the welding joint of the coal powder pipe, the following measures should be taken.

3.1 Before welding, the welding area must be carefully polished to a metallic luster and the groove required for welding must be polished.

3.2 Before alignment, a gap must be reserved and forced alignment is strictly prohibited.

3.3 Welding materials must be used correctly and preheated as required in cold weather.

6、 Regarding preventive measures such as oil system leakage and oil leakage

During the installation of oil pipelines, all flange interfaces or threaded joints must be equipped with oil resistant rubber pads or oil resistant asbestos pads.

2. The leakage points of the oil system are mainly concentrated on the flanges and threaded joints, so the bolts must be tightened evenly when installing the flanges. Prevent situations of tightness or looseness from occurring.

During the oil filtration process, maintenance personnel must always remain at their work posts and are strictly prohibited from leaving or crossing posts.

4. When replacing the oil filter paper, the oil filter mechanism must be stopped.

5. When installing the temporary oil filter connecting pipe (high-strength plastic transparent hose), the joint must be firmly tied with lead wire to prevent oil leakage after the oil filter machine has been running for a long time.